1. Field of the Invention
The present invention is generally in the field of semiconductor fabrication. More specifically, the invention is in the field of fabrication of capacitors in semiconductor dies.
2. Background Art
High performance mixed signal and RF circuits require high-density integrated capacitors. Metal-insulator-metal (“MIM”) capacitors can be considered for use in the fabrication of integrated mixed signal and RF circuits on semiconductor dies. However, typical MIM capacitors have low capacitance density and since RF and mixed signal applications require high capacitance values, the die area consumed by typical MIM capacitors is too large, resulting in increased die cost to the manufacturer.
In a conventional MIM capacitor, a MIM capacitor dielectric is situated between bottom and top metal plates, which form the electrodes of the MIM capacitor. Currently, silicon nitride (SiN) is widely utilized as a MIM capacitor dielectric in the conventional MIM capacitor. In order to increase the capacitance density in a conventional MIM capacitor, the thickness of the MIM capacitor dielectric can be reduced. However, in a conventional MIM capacitor utilizing silicon nitride as the MIM capacitor dielectric, undesirable leakage current can occur if the silicon nitride becomes too thin.
Alternatively, a high dielectric constant (high-k) dielectric having a higher dielectric constant than silicon nitride can be utilized to increase the capacitance density of the MIM capacitor. However, some high-k dielectrics, such as silicon carbide, are difficult to etch and process, while others, such as tantalum oxide, are not ready available.
Thus, there is a need in the art for a cost effective, high-k MIM capacitor dielectric that is easy to manufacture and readily available.